C语言判断当前某一个进程是否存在

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/wait.h>
#define BUFSZ 150
void err_quit(char *msg);
int main(int argc, char *argv[]) {
FILE* fp;
int count;
char buf[BUFSZ];
char command[150];
sprintf(command, "ps -ef | grep ***** | grep -v grep | wc -l" ); //*****代表要监控的进程
if((fp = popen(command,"r")) == NULL)
err_quit("popen");
if( (fgets(buf,BUFSZ,fp))!= NULL ) {
count = atoi(buf);
if(count == 0)
printf("进程不存在!\n");
else
printf("进程已找到，有%d个!\n",count);
}
pclose(fp);
return EXIT_SUCCESS;
}
void err_quit(char *msg) {
perror(msg);
exit(EXIT_FAILURE);
}